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11강_DecisionTree.ipynb

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+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": 8,
+   "source": [
+    "!pip install pydot"
+   ],
+   "outputs": [
+    {
+     "output_type": "stream",
+     "name": "stdout",
+     "text": [
+      "Requirement already satisfied: pydot in c:\\python39-at\\lib\\site-packages (1.4.2)\n",
+      "Requirement already satisfied: pyparsing>=2.1.4 in c:\\python39-at\\lib\\site-packages (from pydot) (2.4.7)\n"
+     ]
+    },
+    {
+     "output_type": "stream",
+     "name": "stderr",
+     "text": [
+      "WARNING: You are using pip version 21.1.3; however, version 21.2.4 is available.\n",
+      "You should consider upgrading via the 'c:\\python39-at\\python.exe -m pip install --upgrade pip' command.\n"
+     ]
+    }
+   ],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 15,
+   "source": [
+    "from sklearn.tree import DecisionTreeClassifier, export_graphviz\r\n",
+    "from sklearn.datasets import load_breast_cancer\r\n",
+    "from sklearn.model_selection import train_test_split\r\n",
+    "\r\n",
+    "#Dot to png\r\n",
+    "import pydot"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 16,
+   "source": [
+    "cancer = load_breast_cancer() #breast cancer dataset 가져오기!!\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 17,
+   "source": [
+    "#훈련, 테스트 데이터 셔플\r\n",
+    "X_train, X_test, y_train, y_test = train_test_split(\r\n",
+    "cancer.data, cancer.target, stratify=cancer.target, random_state=42)\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "source": [
+    "#의사결정 트리 선언\r\n",
+    "dTreeAll = DecisionTreeClassifier(random_state=0)"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "source": [
+    "dTreeAll.fit(X_train, y_train)\r\n"
+   ],
+   "outputs": [
+    {
+     "output_type": "execute_result",
+     "data": {
+      "text/plain": [
+       "DecisionTreeClassifier(random_state=0)"
+      ]
+     },
+     "metadata": {},
+     "execution_count": 21
+    }
+   ],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "source": [
+    "#점수 출력\r\n",
+    "print(\"Train Set Score1 : {:.2f}\".format(dTreeAll.score(X_train, y_train)))\r\n",
+    "print(\"Test  Set Score1 : {:.2f}\".format(dTreeAll.score(X_test, y_test)))\r\n"
+   ],
+   "outputs": [
+    {
+     "output_type": "stream",
+     "name": "stdout",
+     "text": [
+      "Train Set Score1 : 1.00\n",
+      "Test  Set Score1 : 0.94\n"
+     ]
+    }
+   ],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "source": [
+    "\r\n",
+    "#의사결정 트리 선언(트리 깊이 제한)\r\n",
+    "dTreeLimit = DecisionTreeClassifier(max_depth=3, random_state=0)\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "source": [
+    "#훈련 (가지치기 : 리프노드 깊이 제한)\r\n",
+    "dTreeLimit.fit(X_train, y_train)"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "source": [
+    "\r\n",
+    "#점수 출력\r\n",
+    "print(\"Train Set Score2 : {:.2f}\".format(dTreeLimit.score(X_train, y_train)))\r\n",
+    "print(\"Test  Set Score2 : {:.2f}\".format(dTreeLimit.score(X_test, y_test)))\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "source": [
+    "\r\n",
+    "\r\n",
+    "export_graphviz(dTreeLimit, out_file=\"dicisionTree1.dot\", class_names=[\"malignant\",\"benign\"],\r\n",
+    "                feature_names=cancer.feature_names, impurity=False, filled=True)\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "source": [
+    "\r\n",
+    "#Encoding 중요\r\n",
+    "(graph,) = pydot.graph_from_dot_file('dicisionTree1.dot', encoding='utf8')\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "source": [
+    "\r\n",
+    "#Dot 파일을 Png 이미지로 저장\r\n",
+    "graph.write_png('dicisionTree1.png')\r\n"
+   ],
+   "outputs": [],
+   "metadata": {}
+  }
+ ],
+ "metadata": {
+  "orig_nbformat": 4,
+  "language_info": {
+   "name": "python",
+   "version": "3.9.6",
+   "mimetype": "text/x-python",
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "pygments_lexer": "ipython3",
+   "nbconvert_exporter": "python",
+   "file_extension": ".py"
+  },
+  "kernelspec": {
+   "name": "python3",
+   "display_name": "Python 3.9.6 64-bit"
+  },
+  "interpreter": {
+   "hash": "63fd5069d213b44bf678585dea6b12cceca9941eaf7f819626cde1f2670de90d"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 2
+}